Catheters are commonly used invasively to treat cardiovascular diseases through a method known as balloon angioplasty. A catheter is employed having a balloon portion near the catheter's distal end. The balloon portion is placed within an obstructed artery and inflated; expanding outwardly, the balloon dilates the arterial vessel.
Balloon angioplasty procedures when successful avoid bypass surgery and the attendant costs and medical risks thereof. Effective treatment of arterial stenoses, however, may not be realized through current balloon angioplasty methods for a number of reasons. For example, the lumen through the stenosis may be too narrow to permit entry of the deflated balloon catheter. Also, inflation times of currently used balloon catheters may be limited to 15 to 60 seconds due to occlusion of the arterial opening by the inflated balloon. This limited inflation time is often not sufficient to treat the stenosis and inflations must be repeated. Further, even if the arterial lumen is successfully dilated, the effect may be only temporary. Restenosis of the artery after treatment is not uncommon. It is believed, however, that a sustained inflation of the catheter balloon, rather than shorter multiple inflations, would reduce the possibility of such post-treatment restenosis.
A sustained inflation period also permits use of relatively lower inflation pressures. Extended, low pressure inflation tends to compress, rather than tear, plague of an arterial lesion over time. By not tearing the arterial lesion, healing of the dissection is facilitated. In contrast, conventional shorter multiple balloon inflations performed at relatively high inflation pressures could tear the arterial lesion thereby prolonging recovery or entirely preventing successful treatment.